package main

import (
    "fmt"
    "sync"
)

type Resp struct {
    Msg string
}

func main(){

    // unbuffered channel to capture response from the go routine
    ch:=make(chan Resp)

    // sync.WaitGroup type for handling go routines
    var wg sync.WaitGroup

    for i:=1;i<=5;i++{
        // tell WaitGroup to that you are going totrigger a go routine
        wg.Add(1)

        // trigger
        go routine(&wg,i,ch)

    }

    // fire a go routine to run as demon and give a way to read the response
    // and it will wait until all go routines executed successfully
    go func(){

        // wait until all goroutines are executed successfully
        wg.Wait()

        // we have to close the channel else below for loop will wait for data to write but data won't come
        // this will lead to a deadlock (infinite wait)
        close(ch)

    }()

    // read from response channel
    for v:=range ch{
        fmt.Println(v.Msg)
    }

    fmt.Println("signing off ...!!!")

}

func routine(wg *sync.WaitGroup,i int,ch chan Resp){
    // tell waitGroup that you are done with this task
    defer wg.Done()

    //send data to response channel
    ch<-Resp{
        Msg: fmt.Sprintf("completed task %d..!!",i),
    }

}

output:-
completed task 4..!!
completed task 3..!!
completed task 5..!!
completed task 1..!!
completed task 2..!!
signing off ...!!!